Do you need to know, when is the best time to go to Mauritania? Then you should take a look here, what weather you can expect there during the year.
The climate of Mauritania is hot, dry and dusty. There is only very few rains, temperatures are usually very high and they don't change much during the year. Sometimes even several years may pass without any rain in some locations of Sahara, temperatures may be high during day, but very low during night, especially in winter. Weather may be more pleasant at the coastal and in the valley of the Senegal river.
When speaking about the usual weather in this state, the information is relevant for example for these popular places: Atar, Azougi, Banc d'Arguin National Park, Chinguetti, Choum, Coastal Mauritania, Nouadhibou, Nouakchott, Saharan Mauritania, Sahelian Mauritania, Tichit.
Let's look now what weather you can expect here. (Warning: As we don't have reliable data for this country, we use data from nearby locations for these statistics.) The warmest month here is May, the average maximum temperature is 41.3 ℃ (106.34 ℉). The average minimum temperature in this month is 19.2 ℃ (66.56 ℉). The coldest month here is January, the average maximum temperature is 31 ℃ (87.8 ℉). The average minimum temperature in this month is 11.6 ℃ (52.88 ℉). 
When travelling to some places in Mauritania, always consider the altitude of the the place as well. The highest point here is Kediet Ijill (915 m) and the lowest point is Sebkhet Te-n-Dghamcha (-5 m). So there are not big differences in altitudes in this country. But the altitude affects the weather even so. Keep in mind, that the temperature usually decreases by 1.2 - 1.9 ℃ (2.2 - 3.5 ℉) per 200 m (656 ft), depending on the other conditions. (And we should add, that in the very special condition named thermal inversion even the temperature may be higher in higher altitudes.)
Typical (usual) weather in Mauritania in January is this: The average highest temperature in Mauritania in January is 31 ℃ (87.8 ℉). The average lowest temperature is 11.6 ℃ (52.88 ℉). At the beginning of January you can expect higher temperatures, the average highest temperature is around 31.9 ℃ (89.42 ℉). At the end of January you can expect higher temperatures, the average highest temperature is around 32.5 ℃ (90.5 ℉). The average rainfall is 0.9 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 11:09 (hours and minutes), in the middle of the month 11:14 and at the end of the month 11:23.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes.Typical (usual) weather in Mauritania in February is this: The average highest temperature in Mauritania in February is 34 ℃ (93.2 ℉). The average lowest temperature is 13.5 ℃ (56.3 ℉). At the beginning of February you can expect lower temperatures, the average highest temperature is around 32.5 ℃ (90.5 ℉). At the end of February you can expect higher temperatures, the average highest temperature is around 36.05 ℃ (96.89 ℉). The average rainfall is 1.5 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 11:23 (hours and minutes), in the middle of the month 11:35 and at the end of the month 11:48.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes.Typical (usual) weather in Mauritania in March is this: The average highest temperature in Mauritania in March is 38.1 ℃ (100.58 ℉). The average lowest temperature is 15.2 ℃ (59.36 ℉). At the beginning of March you can expect lower temperatures, the average highest temperature is around 36.05 ℃ (96.89 ℉). At the end of March you can expect higher temperatures, the average highest temperature is around 38.5 ℃ (101.3 ℉). The average rainfall is 0.6 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 11:48 (hours and minutes), in the middle of the month 12:02 and at the end of the month 12:17.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes.Typical (usual) weather in Mauritania in April is this: The average highest temperature in Mauritania in April is 38.9 ℃ (102.02 ℉). The average lowest temperature is 17.2 ℃ (62.96 ℉). At the beginning of April you can expect lower temperatures, the average highest temperature is around 38.5 ℃ (101.3 ℉). At the end of April you can expect higher temperatures, the average highest temperature is around 40.1 ℃ (104.18 ℉). The average rainfall is 0.2 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:17 (hours and minutes), in the middle of the month 12:30 and at the end of the month 12:43.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes.Typical (usual) weather in Mauritania in May is this: The average highest temperature in Mauritania in May is 41.3 ℃ (106.34 ℉). The average lowest temperature is 19.2 ℃ (66.56 ℉). At the beginning of May you can expect lower temperatures, the average highest temperature is around 40.1 ℃ (104.18 ℉). At the end of May you can expect lower temperatures, the average highest temperature is around 41 ℃ (105.8 ℉). The average rainfall is 0.1 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:43 (hours and minutes), in the middle of the month 12:54 and at the end of the month 13:02.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes.Typical (usual) weather in Mauritania in June is this: The average highest temperature in Mauritania in June is 40.7 ℃ (105.26 ℉). The average lowest temperature is 21.1 ℃ (69.98 ℉). At the beginning of June you can expect higher temperatures, the average highest temperature is around 41 ℃ (105.8 ℉). At the end of June you can expect lower temperatures, the average highest temperature is around 39.3 ℃ (102.74 ℉). The average rainfall is 1 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 13:02 (hours and minutes), in the middle of the month 13:06 and at the end of the month 13:06.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes.Typical (usual) weather in Mauritania in July is this: The average highest temperature in Mauritania in July is 37.9 ℃ (100.22 ℉). The average lowest temperature is 22.4 ℃ (72.32 ℉). At the beginning of July you can expect higher temperatures, the average highest temperature is around 39.3 ℃ (102.74 ℉). At the end of July you can expect lower temperatures, the average highest temperature is around 37.65 ℃ (99.77 ℉). The average rainfall is 40.9 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 13:06 (hours and minutes), in the middle of the month 13:02 and at the end of the month 12:53.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes.Typical (usual) weather in Mauritania in August is this: The average highest temperature in Mauritania in August is 37.4 ℃ (99.32 ℉). The average lowest temperature is 22.4 ℃ (72.32 ℉). At the beginning of August you can expect higher temperatures, the average highest temperature is around 37.65 ℃ (99.77 ℉). At the end of August you can expect higher temperatures, the average highest temperature is around 37.7 ℃ (99.86 ℉). The average rainfall is 76 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:53 (hours and minutes), in the middle of the month 12:43 and at the end of the month 12:30.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes.Typical (usual) weather in Mauritania in September is this: The average highest temperature in Mauritania in September is 38 ℃ (100.4 ℉). The average lowest temperature is 22.9 ℃ (73.22 ℉). At the beginning of September you can expect lower temperatures, the average highest temperature is around 37.7 ℃ (99.86 ℉). At the end of September you can expect lower temperatures, the average highest temperature is around 37.95 ℃ (100.31 ℉). The average rainfall is 74.1 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:30 (hours and minutes), in the middle of the month 12:16 and at the end of the month 12:02.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes.Typical (usual) weather in Mauritania in October is this: The average highest temperature in Mauritania in October is 37.9 ℃ (100.22 ℉). The average lowest temperature is 19.4 ℃ (66.92 ℉). At the beginning of October you can expect higher temperatures, the average highest temperature is around 37.95 ℃ (100.31 ℉). At the end of October you can expect lower temperatures, the average highest temperature is around 36.7 ℃ (98.06 ℉). The average rainfall is 15.4 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:02 (hours and minutes), in the middle of the month 11:49 and at the end of the month 11:35.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes.Typical (usual) weather in Mauritania in November is this: The average highest temperature in Mauritania in November is 35.5 ℃ (95.9 ℉). The average lowest temperature is 17.3 ℃ (63.14 ℉). At the beginning of November you can expect higher temperatures, the average highest temperature is around 36.7 ℃ (98.06 ℉). At the end of November you can expect lower temperatures, the average highest temperature is around 34.15 ℃ (93.47 ℉). The average rainfall is 0.3 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 11:35 (hours and minutes), in the middle of the month 11:24 and at the end of the month 11:14.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes.Typical (usual) weather in Mauritania in December is this: The average highest temperature in Mauritania in December is 32.8 ℃ (91.04 ℉). The average lowest temperature is 12.3 ℃ (54.14 ℉). At the beginning of December you can expect higher temperatures, the average highest temperature is around 34.15 ℃ (93.47 ℉). At the end of December you can expect lower temperatures, the average highest temperature is around 31.9 ℃ (89.42 ℉). The average rainfall is 0.7 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 11:14 (hours and minutes), in the middle of the month 11:09 and at the end of the month 11:08.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes.